Telephone-transmitter.



. I. .l A A .l

PATENTED APR/18, 1905.

J ERICKSON TELEPHUNE TRANSMITTER.

APPLIOATION FILED MAY 4,1903. BENEWED 00T.a.19o4.

mmm/,361.

' w'lT UaTTen STaTns Patented April 18, 1905.

PATENT OFFICE,

A UTO )ITIC TELEPHONE NOlb.

EXCHANGE, A CORPORATION OF ILLI- TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 787,361, dated. April 18, 1905.

Application filed May 4, 1903. Renewed October 3, 1904. Serial No. 227,022.

VBe it known that I, ,Tous Emcksox, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a new and useful Telephone- 'l`ransmitter, of which the Yfollowing isa specitieation.

My invention relates to telephone-transmitters; and my object is to produce a simple construction which is particularly sensitive to the action of sound-waves, vet is not easily rendered inoperative by any ordinary usage, the same being described hereinafter and illustrated in the accompanyingdrawings, in which Figure l is a vertical axial section of the front end portion of the supportingarm, showing the bell thereof and the cap and mouthpiece therefor, together with the transmitter mechanism, which is fully described hereinafter. Figs. 2, 3, and 4 are respectively a side and front elevation and a section on line A B, Fig. 3, of the transmittercase which is secured within the bell of the supporting-arm. Figs. 5 and 6 are respectively a side and an end elevation of an electrodel and the means b v which it is attached to but insulated from the case shown in Figs. L), 3, and I. Figs. T, S, and 9 show, respectively, a side and front elevation and a section on line t l), Fig. 8, of a cup-shaped electrode which is attached to the central portion of the transmitter-diaphragm and disposed in opposition to the electrode shown in Figs. 5 and (3. Figs. lO and l1 are respectively side and edge elevations of a compound circular spring for holding the transmitterdiaphragm in yielding contact and electrical comiection with a peripheral seat in the transmitter-case. Fig. l2 is a front elevation of the transmitterdiaphragm, showing central hole for attachment of the electrode illustrated in Figs. T, H, and t). Figs. 13 and l-L are respectively side and edge elevations of a hollow cylinder of felt which serves as a packing for the granulated-carbon chamber and a resilient means for holding the hereinbeforementioned electrodes in the proper lyielding position.

Similar numerals indicate like throughout the several views.

The arm or support l in this instance is hollow and is usually pivotally attached to some stationary object at the opposite end portion from the transmitter and not shown in the drawings. At the free end of arm 1 is abell-shaped portion 2, which is externally scre\\'threaded to receive an intcrnally-screwthreaded cap 3, to which the mouthpiece is secured.

The metal transmitter-case I is provided with an axial cylindrical portion having a hole at 5, which is lilled with insulating material (j, into which latter is secured a metal electrode T, upon whose inner end within case I is attached, in this instance, a carbon face 8. The interspace around this electrode, between it and the inside walls of the case si, is filled with a felt packingf), Figs. 1, 13, and 14:, and in contact with the outer end of this packing is the rim of a cup-shaped, in this instance carbon, electrode ll, which is secured to the center of transmittor-diaphragm 10, as seen in Fig. l, the diaphragm having a portion of its peripheral margin in contact and electrical connection with the shoulder 12 around the inside peripheral portion of case I.

Closely adjacent to the transmitter-diaphragm, but with the main body portion in Contact with the inside surface of cap 3, is a compound spring 12S, having several resilient arms 11, which contact the peripheral portion of diaphragm and hold ityieldingly in position. Since the periphery of case -L is screwthreaded, it may be screwed into some desired position, so that the spring-arms l-I have the proper pressure upon diaphragm l0 and the electrode 1l be also held in position, as shown in Fig. 1, with the Vfront annular edge in contact with the packing of felt 9, preferably between its outer and inner edges, to form between the inner surface of the bottom and sides of electrode 11 and the surface of the sides and end of electrode e an interspace, which is lilled almost full of granular carbon 15. 'lhe inner wall of the cup is straight and parallel with the exterior of the electrode 8, so that the loose carbon cannot wedge beparts tween them, and thereby interfere with the free vibration of the diaphragm, and the exterior wall of the cup is preferably beveled or inclined to form the edge very thin, which will retain the carbon, but will give the least possible surface to bear against the packing 9, which encircles the electrode S, thereby reducing' the pressure to be overcome to a minimum in forcing the cup inward when the diaphragm is vibrated.

A wire 16 is secured to the rear end of electrode 7, which, with the carbon facing 8 thereon, forms one electrode, and another wire 17 is attached to the transmitter-case 4, which is in electrical communication by contact with metal diaphragm l0, to which the opposite electrode ll is attached, so that wires 16 and 17 form part of an electric circuit in which is included` in this instance, an electric battery and the primary of an induction-coil, the secondary of the latter being connected with a telephone-receiver, all of which latterdescribed parts are not shown.

I claim as my invention4 1. In a telephone-transmitter, a case, a diaphragm, two electrodes in the case, one of which'is stationary and the other one is cupshaped and secured to the diaphragm with its cup surrounding the stationary electrode with an interspace therebetween, a packing' surrounding' the stationary electrode with its inner edge engaging therewith and its outer surface engaging the edge of the cup, and granular material within the space between the electrodes for the purpose stated.

2. In a telephone-transmitter, a perforated case, a diaphragm opposite the perforation, two electrodes, one of which is stationary and projects through the perforation and the other one is cup-shaped and secured to the diaphragm with its cup surrounding the inner end of the stationary electrode and forming an interspace therebetween, a ring of packing material surrounding the stationary electrode' and in engagement therewith, one face of the ring engaging the case and the other face engaging the edge of the cup, said edge being intermediate the outer and inner edges of the ring', means for holding said edge in constant contact with said surface, and granular material within the space between the electrodes, for the purpose stated.

8. In a telephone-transmitter a casing comprising' side and end walls, an electrode insulatingly disposed through the en d wall and terthe electrode, a cup-shaped electrode secured at the center of the diaphragm, and the open end thereof partially inclosing the first-named electrode and in contact with the librous material, and a partial filling of granulated carbon between the electrodes, for the purpose stated.

4. In a telephone-transmitter, a case, an electrode therein, a packing encircling the electrode, a diaphragm, a cup-shaped electrode on the diaphragm, the interior of which is of a greater diameter than the other electrode with its internal wall parallel with the sides of said other electrode, and the external wall inclined to form a thin edge, said edge beingin contact with the first-mentioned electrode.

5. In a telephone-transmitter, a perforated case provided with a cylindrical portion, an annular packing in said portion, an electrode having a projection extending through the perforation and the packing, a diaphragm for the case, a cup-like electrode secured thereto and partially inclosing the other electrode and engaging with the packing with its rim, and granular material in the interspace between the electrodes. 6. In a telephone-transmitter, a case, the periphery of which is screw-threaded, an electrode in the case, an annular packing around the electrode, a diaphragm for th'e case, a cuplike electrode secured thereto and partially inclosing the other electrode and engaging with the packing, granular material between the electrodes, an internally-screw-threaded cap on the case, and a compound spring between the cap and the case and provided with resilient arms, for the purpose stated.

In testimony whereof I have signed my name I to this specification in the presence of two subscribing witnesses.

JOHN ERICKSON. Vitnesses:

SAMUEL COLE, OSCAR SNELL. 

